scholarly journals Saliva Quantification of SARS-CoV-2 in Real-Time PCR From Asymptomatic or Mild COVID-19 Adults

2022 ◽  
Vol 12 ◽  
Author(s):  
Florence Carrouel ◽  
Emilie Gadea ◽  
Aurélie Esparcieux ◽  
Jérome Dimet ◽  
Marie Elodie Langlois ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Real Time Pcr ◽  
Clinical Symptoms ◽  
Age Groups ◽  
Nasal Discharge ◽  
Viral Loads ◽  
Co Morbidity ◽  
Significant Difference ◽  
The Relationship

The fast spread of COVID-19 is related to the highly infectious nature of SARS-CoV-2. The disease is suggested to be transmitted through saliva droplets and nasal discharge. The saliva quantification of SARS-CoV-2 in real-time PCR from asymptomatic or mild COVID-19 adults has not been fully documented. This study analyzed the relationship between salivary viral load on demographics and clinical characteristics including symptoms, co-morbidities in 160 adults diagnosed as COVID-19 positive patients recruited between September and December 2020 in four French centers. Median initial viral load was 4.12 log10 copies/mL (IQR 2.95–5.16; range 0–10.19 log10 copies/mL). 68.6% of adults had no viral load detected. A median load reduction of 23% was observed between 0–2 days and 3–5 days, and of 11% between 3–5 days and 6–9 days for the delay from onset of symptoms to saliva sampling. No significant median difference between no-symptoms vs. symptoms patients was observed. Charge was consistently similar for the majority of the clinical symptoms excepted for headache with a median load value of 3.78 log10 copies/mL [1.95–4.58] (P < 0.003). SARS-CoV-2 RNA viral load was associated with headache and gastro-intestinal symptoms. The study found no statistically significant difference in viral loads between age groups, sex, or presence de co-morbidity. Our data suggest that oral cavity is an important site for SARS-CoV-2 infection and implicate saliva as a potential route of SARS-CoV-2 transmission.

scholarly journals Quantitative Analysis of Human Herpesvirus 8 Viral Load Using a Real-Time PCR Assay

2000 ◽  
Vol 38 (4) ◽  
pp. 1404-1408 ◽  
Author(s):  
Francis Lallemand ◽  
Nathalie Desire ◽  
Willy Rozenbaum ◽  
Jean-Claude Nicolas ◽  
Vincent Marechal
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Clinical Symptoms ◽  
Human Herpesvirus ◽  
Human Herpesvirus 8 ◽  
Clinical Samples ◽  
Taqman Assay ◽  
Published Data ◽  
Herpesvirus 8 ◽  
Viral Loads

We have developed a quantitative real-time PCR (TaqMan) assay aimed at measuring the cellular human herpesvirus 8 (HHV-8) DNA load in various clinical samples. Standard curves were obtained by serial dilutions of a control plasmid containing both HHV-8 (ORF73 gene) and the cellular target (human albumin gene). The assay appeared to be very sensitive (100% detection rate for at least 10 copies per well) and specific and was easily reproducible (less than 3% intra-assay variability, 5% interassay variability). This method allowed us to quantify precisely the average HHV-8 copy number per cell in various persistently HHV-8-infected cell lines (BBG-1 cells, n= 200; BC-1 cells, n = 59; BCBL-1 cells,n = 70). A retrospective study was also conducted to assess the HHV-8 DNA load in 12 human immunodeficiency virus-infected patients with either Kaposi's sarcoma (KS; seven patients monitored over a 3-month period) or multicentric Castleman's disease (MCD; five patients). The HHV-8 DNA load ranged from 0 to 9,171 copies/106 cells in low-risk KS patients (T0, I0, S0 according to the classification of the AIDS Clinical Trials group). We also measured the viral loads in MCD patients either during symptomatic periods or during remission. The results are in agreement with previously published data, with high viral loads correlating with clinical symptoms (1.3 × 106 copies/106cells) and low viral loads correlating with asymptomatic periods (less than 5,000 copies/106 cells).

scholarly journals Association of Viral Load in SARS-CoV-2 Patients With Age and Gender

2021 ◽  
Vol 8 ◽  
Author(s):  
Waleed H. Mahallawi ◽  
Ali Dakhilallah Alsamiri ◽  
Alaa Faisal Dabbour ◽  
Hamdah Alsaeedi ◽  
Abdulmohsen H. Al-Zalabani
Keyword(s):  
Viral Load ◽  
Clinical Symptoms ◽  
Age Groups ◽  
Global Public Health ◽  
Surveillance Network ◽  
Ct Value ◽  
Significant Difference ◽  
The Difference ◽  
Mean Differences ◽  
Age And Sex

Background: The coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a global public health emergency. Age and sex are two important factors associated with risks and outcomes of various diseases. COVID-19 morbidity also seems to be affected by patient age and sex. It has been found that older age groups have more severe COVID-19 symptoms and higher fatality rates while children tend to have lower prevalence and milder symptoms than adults.Methods: The study reviewed electronic medical records of COVID-19 patients from Madinah city, Saudi Arabia. The study included all cases who tested positive (n = 3,006) between March 20 and May 22, 2020. Data were obtained from the Health Electronic Surveillance Network (HESN) database.Results: Approximately 80% of the study sample were males and half were in the 30–40-year-old age group. The Ct value of the whole sample ranged from 15.08 to 35, with a mean of 27.44 (SD: 5.23; 95% C.I. = 27.25–27.66). The means of Ct values varied between age groups from 27.05 to 27.82. Analysis of the mean differences between age groups using one-way ANOVA indicated no statistically significant difference among the groups (F6,2999 = 1.63; p-value = 0.135). A comparison of mean Ct values of males (n = 2,422) and females (n = 584) revealed that males had a statistically significant higher mean Ct value (27.61 ± 5.20) than females (26.72 ± 5.31). The difference between the means of the two groups was −0.89 (95% C.I. = −1.36 to −0.42; t-test −3.71; df = 3,004; p-value < 0.001).Conclusion: The study found no statistically significant difference in viral loads between age groups. It showed that females had a higher SARS-CoV-2 viral load compared to males. The findings have implications for preventive strategies. Further studies are needed to correlate viral load with clinical symptoms and outcomes.

scholarly journals Real-Time PCR Detection Patterns of Porcine Circovirus Type 2 (PCV2) in Polish Farms with Different Statuses of Vaccination against PCV2

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1135 ◽  
Author(s):  
Aleksandra Woźniak ◽  
Dagmara Miłek ◽  
Piotr Matyba ◽  
Tomasz Stadejek
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Porcine Circovirus ◽  
Quantitative Real Time Pcr ◽  
Viral Loads ◽  
Oral Fluids ◽  
Significant Difference

Porcine circovirus type 2 (PCV2) is a globally spread pathogen controlled with generally highly efficacious vaccination protocols. In order to compare PCV2 detection profiles in farms with different vaccination statuses, serum (359) and fecal pools (351) and oral fluids (209) from four farms that do not vaccinate against PCV2 (NON-VAC) and from 22 farms that do vaccinate (VAC) were tested with quantitative real-time PCR. Additionally, nucleotide sequences of ORF2 of the virus were obtained from selected samples. Three genotypes, PCV2a, PCV2b, and PCV2d, were detected. Significant differences (p < 0.05) in PCV2 prevalence and quantities between the VAC and NON-VAC farms were evident. In five VAC farms, no viremia or shedding in feces was detected. On the other hand, in four VAC farms, the results were very similar to those from NON-VAC farms. No significant difference in PCV2 prevalence in oral fluids was observed between VAC and NON-VAC farms. An examination of viremia can be recommended for the detection of vaccination efficacy issues. The median of the PCV2 viral loads >6.0 log10 copies/mL in pooled sera from the vaccinated population should be considered a very strong indication that the vaccination protocol needs revision.

scholarly journals Whatman FTA cards versus plasma specimens for the quantitation of HIV-1 RNA using two real-time PCR assays

2020 ◽  
Vol 2 (8) ◽  
Author(s):  
Abdourahamane Yacouba ◽  
Malika Congo ◽  
Gérard Komonsira Dioma ◽  
Hermann Somlare ◽  
David Coulidiaty ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Filter Paper ◽  
Real Time Pcr ◽  
Load Testing ◽  
Viral Loads ◽  
Viral Load Testing ◽  
Fta Cards ◽  
Pcr Assays ◽  
Hiv 1

Background. Several studies have compared the use of dried blot spot (DBS) as an alternative to plasma specimens, mainly using Whatman 903 cards as filter paper. The aim of this study was to evaluate the use of Whatman FTA card (FTA card) specimens for HIV-1 viral load testing compared to plasma specimens using two real-time PCR assays manufactured by Roche and Abbott. Methodology. A cross-sectional study was conducted between April 2017 and September 2017 on HIV-1 patients admitted to Yalgado Ouédraogo Teaching Hospital. Paired FTA cards and plasma specimens were collected and analysed using the Abbott Real-Time HIV-1 assay (Abbott) and COBAS AmpliPrep/COBAS TaqMan v2.0 (Roche). Results. In total, 107 patients were included. No statistical differences (P>0.05) were observed between the mean viral loads obtained from the FTA cards and those of the plasma specimens using the Roche and Abbott assays. In total, 29 samples with Roche and 15 samples with Abbott assay showed discrepant results. At viral loads of ≤1000 copies ml−1, the sensitivity and specificity of the FTA cards were 78.6 and 100% with Roche, and 92.3 and 95.9% with Abbott, respectively. Both the Roche and Abbott assays showed good correlation and agreement between the FTA cards and plasma values. Conclusion. Our study demonstrates the feasibility of using FTA card filter paper for HIV-1 viral load testing. However, further studies will be required for the validation of the use of FTA card filter paper in HIV-1 treatment monitoring.

scholarly journals Usefulness of a real-time PCR platform for G+C content and DNA–DNA hybridization estimations in vibrios

2011 ◽  
Vol 61 (10) ◽  
pp. 2379-2383 ◽  
Author(s):  
Ana Paula B. Moreira ◽  
Nei Pereira ◽  
Fabiano L. Thompson
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dna Hybridization ◽  
Sister Species ◽  
Wide Range ◽  
Significant Difference ◽  
The Mean ◽  
Vibrio Campbellii ◽  
The Relationship ◽  
Linear Regression Curve

The aim of this study was to evaluate the utility of a real-time PCR platform to estimate the DNA G+C content (mol%) and DNA–DNA hybridization (DDH) values in the genus Vibrio. In total, nine vibrio strains were used to determine the relationship between genomic DNA G+C content and T m (°C). The T m and HPLC datasets fit a linear regression curve with a significant correlation coefficient, corroborating that this methodology has a high correlation with the standard methodology based on HPLC (R2 = 0.94). Analysis of 31 pairs of vibrios provided a wide range of ΔT m values, varying between 0.72 and 12.5 °C. Pairs corresponding to strains of the same species or strains from sister species showed the lowest ΔT m values. For instance, the ΔT m of the sister species Vibrio harveyi LMG 4044T and Vibrio campbellii LMG 11216T was 5.2 °C, whereas the ΔT m of Vibrio coralliilyticus LMG 20984T and Vibrio neptunius LMG 20536T was 8.75 °C. The mean ΔT m values corresponding to pairs of strains with DDH values lower than 60 % or higher than 80 % were, respectively, 8.29 and 2.21 °C (significant difference, P<0.01). The high correlation between DDH values obtained in previous studies and the ΔT m values (R2 = 0.7344) indicates that the fluorimetric methodology is a reliable alternative for the estimation of both DNA G+C content and ΔT m in vibrios. We suggest that strains of the same Vibrio species will have less than 4 °C ΔT m. The use of a real-time PCR platform represents a valuable alternative for the development of the taxonomy of vibrios.

scholarly journals Anchor-Based Fluorescent Amplicon Generation Assays (FLAG) for Real-Time Measurement of Human Cytomegalovirus, Epstein–Barr Virus, and Varicella-Zoster Virus Viral Loads

2008 ◽  
Vol 54 (11) ◽  
pp. 1900-1907 ◽  
Author(s):  
Alessandro Di Nicola ◽  
Elisa Ghezzi ◽  
Federico Gillio ◽  
Francesco Zerilli ◽  
Erlet Shehi ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Human Cytomegalovirus ◽  
Real Time Pcr ◽  
Epstein Barr Virus ◽  
Varicella Zoster ◽  
Viral Loads ◽  
Barr Virus ◽  
Epstein Barr ◽  
Diagnostic Sensitivity And Specificity

Abstract Background: Monitoring the human cytomegalovirus (HCMV), Epstein–Barr virus (EBV), or varicella-zoster virus (VZV) viral load is an important factor in the management of immunosuppressed patients, such as recipients of solid-organ or bone marrow transplants. The advent of real-time PCR technologies has prompted the widespread development of quantitative PCR assays for the detection of viral loads and other diagnostic purposes. Methods: The fluorescent amplicon generation (FLAG) technology uses the PspGI restriction enzyme to monitor PCR product generation. We modified the FLAG technology by introducing an accessory oligonucleotide “anchor” that stabilizes the binding of the forward primer to the target sequence (a-FLAG). We developed assays for HCMV, EBV, and VZV that incorporated an internal amplification-control reaction to validate negative results and extensively analyzed the performance of the HCMV a-FLAG assay. Results: The 3 assays performed similarly with respect to reaction efficiency and linear range. Compared with a commercially available kit, the HCMV a-FLAG assay results showed good correlation with calculated concentrations (r = 0.9617), excellent diagnostic sensitivity and specificity (99% and 95%, respectively), and similar values for the linear range (1–107 copies/μL), analytical sensitivity (0.420 copies/μL), and intra- and interassay imprecision. Conclusions: The a-FLAG assay is an alternative real-time PCR technology suitable for detecting and quantifying target-DNA sequences. For clinical applications such as the measurement of viral load, a-FLAG assays provide multiplex capability, internal amplification control, and high diagnostic sensitivity and specificity.

scholarly journals Mutual predators: A descriptive cross-sectional study to identify prevalence and co-relation of Hepatitis C Virus and Human Immunodeficiency Virus type-1 coinfection

2015 ◽  
Author(s):  
Fouzia Ashraf ◽  
Dalaq Aiysha ◽  
Muhammad Tajamal ◽  
Shahzeb Shahzeb Javed ◽  
Saamia Saamia Tahir ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Viral Load ◽  
Hepatitis C ◽  
Real Time ◽  
Real Time Pcr ◽  
Sample Population ◽  
Plasma Samples ◽  
Viral Loads ◽  
Hiv Type 1

Background: Coinfection, bacterial or viral origin, in HIV infected individuals remains to be the only leading cause of deaths. This study was designed to analyze received plasma samples and plasma samples of referred patients for HIV testing to detect HIV and HCV mono and co-infection by real time PCR and finding co-relation of viral load of both viruses. Highlight and magnify the hidden coinfection, prior to seroconversion, of HIV type-1 and Hepatitis C Virus in received samples. Methods: Analyses were based on randomly selected 78 patients’ stored plasmas. Plasma samples were tested for both, HIV-type 1 and HCV viral RNA by real time PCR. Statistical formulas were used to identify men and the inter quartile range of patients age. The data were analyzed by IBM SPSS Statistics 21 (SPSS Inc., Chicago, IL). Study variables include gender, age and viral loads of HIV type-1 and HCV. Pearson correlation was used to evaluate any correlation in study variables. Result: Prevalence of HCV was 10.3%, HIV-type 1 was 19.2% and their co-infection was 37.2 percent. Thirty three percent individuals had no infection of both viruses. Gender based distribution showed that 74.4% (58/78) sample population was male. The mono-infection and co-infection was higher in males (39.7%) and highest viral load too. There was a positive correlation (CI= 95%) between the two variables; HIV and HCV viral loads, as r = 0.736, n=29, p= 0.001. Conclusion: Prevalence of HIV type-1 and HCV mono-infection and co-infection was higher among males as compared to females. Increased viral load was also evident among male co-infected individuals. This study proved the emergence of HCV coinfection in HIV infected individuals, and a need for on time diagnosis and treatment. I

scholarly journals Comparison and correlation of commercial SARS-CoV-2 real-time-PCR assays, Ireland, June 2020

2021 ◽  
Vol 26 (6) ◽  
Author(s):  
Anne Carroll ◽  
Eleanor McNamara
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Real Time Pcr ◽  
Viral Loads ◽  
Viral Culture ◽  
Pcr Assays ◽  
Result Interpretation

We report the performance of a variety of commercially available SARS-CoV-2 PCR kits, used in several different sites across Ireland to determine if Ct values across platforms are comparable. We also investigate whether a Ct value, a surrogate for calculated viral loads in the absence of viral culture of > 34 can be used to exclude SARS-CoV-2 infection and its complications. We found a variation in Ct values from different assays for the same calculated viral load; this should be taken into consideration for result interpretation.

scholarly journals More DNA and RNA of HBV SP1 splice variants are detected in genotypes B and C at low viral replication

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ka-Cheung Luk ◽  
Jeffrey Gersch ◽  
Barbara J. Harris ◽  
Vera Holzmayer ◽  
Dora Mbanya ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Real Time Pcr ◽  
Splice Variant ◽  
Splice Variants ◽  
Pcr Primers ◽  
Quantitative Real Time Pcr ◽  
Viral Loads ◽  
Hbv Genotypes ◽  
Dna And Rna

AbstractHBV produces unspliced and spliced RNAs during replication. Encapsidated spliced RNA is converted into DNA generating defective virions that are detected in plasma and associated with HCC development. Herein we describe a quantitative real-time PCR detection of splice variant SP1 DNA/RNA in HBV plasma. Three PCR primers/probe sets were designed detecting the SP1 variants, unspliced core, or X gene. Plasmids carrying the three regions were constructed for the nine HBV genotypes to evaluate the three sets, which were also tested on DNA/RNA extracted from 193 HBV plasma with unknown HCC status. The assay had an LOD of 80 copies/ml and was equally efficient for detecting all nine genotypes and three targets. In testing 84 specimens for both SP1 DNA (77.4%) and RNA (82.1%), higher viral loads resulted in increased SP1 levels. Most samples yielded < 1% of SP1 DNA, while the average SP1 RNA was 3.29%. At viral load of ≤ 5 log copies/ml, the detectable SP1 DNA varied by genotype, with 70% for B, 33.3% for C, 10.5% for E, 4% for D and 0% for A, suggesting higher levels of splicing in B and C during low replication. At > 5 log, all samples regardless of genotype had detectable SP1 DNA.

Detection of SARS-CoV-2 RNA in nasopharyngeal swabs from COVID-19 patients and asymptomatic cases of infection by real-time and digital PCR

2020 ◽  
Vol 65 (12) ◽  
pp. 785-792
Author(s):  
V. A. Ternovoi ◽  
R. Yu. Lutkovsky ◽  
E. P. Ponomareva ◽  
A. V. Gladysheva ◽  
E. V. Chub ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Real Time Pcr ◽  
Clinical Symptoms ◽  
False Negative ◽  
Digital Pcr ◽  
Viral Rna ◽  
Laboratory Research ◽  
Low Concentration ◽  
Negative Results

In this work we tested two reagent kits developed by us for detecting SARS-CoV-2 RNA using a fragment of the ORF1ab gene in digital PCR and real-time PCR formats. Data were obtained on the detection of SARS-CoV-2 virus RNA in nasopharyngeal swabs of patients with COVID-19 and asymptomatic carriers. The developed reagent kits provided 100% sensitivity and a detection limit of 103 GE / ml for qPCR, and at least 200 copies / ml of viral RNA when performing digital PCR. These methods were tested using a panel of 1,328 samples collected from patients with suspected COVID-19 at the beginning of 2020 in the Russian Federation. It has been shown that dPCR is more sensitive and can be used to analyze samples with low viral load, including those from patients without clinical symptoms. dPCR significantly improves the accuracy of laboratory research and significantly reduces the number of false negative results in the diagnosis of SARS-CoV-2. Determination of the concentration of SARS-CoV-2 RNA in patients with different clinical course of the disease showed that the concentration of viral RNA can sharply decrease in the first days of the disease. A low concentration of viral RNA in samples from patients is also characteristic of asymptomatic disease. Digital PCR provides a higher detection rate for asymptomatic cases, which is approximately 75% of those infected, as opposed to 45% for real-time PCR. The results obtained on the use of the digital PCR method for detecting SARS-CoV-2 RNA showed that this method is especially suitable for detecting RNA in case of its low concentration in contacts, as well as for monitoring changes in viral load in convalescent patients.

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